I hit my head on a cabinet whiles getting up.had no symptom.the next day had scalp pain and two days after had what feels like a tension headache and tightness around my head.went to the er and she said no sign of serious head injury. still worried?

Good that the ER doc said you had no serious head injury.Not sure if they said no concussion? Concussion symptoms can last for weeks, so try not to worry.However,if the symptoms continue or you have vomiting or any other new symptoms,you should be rechecked.Also recommend not doing strenuous exercise(physical rest)or being on your computer or phone too much(brain rest)until your symptoms are gone.

Closed head injuries can result in several headache varieties, one being focal tension headache like you describe. No need to worry, as it will depart over several days. As mentioned, nausea, vomiting, blurring or doubling of vision, dizziness, imbalance, would be reasons to pursue this further, but I doubt this will occur.